Field of the Invention
The present invention relates to a three-dimensional shape measurement device, a three-dimensional shape measurement method, and a three-dimensional shape measurement program.
Discussion of the Background
Non-Patent Literature 1 describes an example of a technique of generating a three-dimensional model of an object on the basis of a plurality of two-dimensional images containing the object imaged while an imaging unit is moved. In the three-dimensional shape measurement system described in Non-Patent Literature 1, a three-dimensional model of an object is generated as follows. Firstly, the entire object is imaged as a dynamic image while a stereo camera configuring an imaging unit is moved. Such a stereo camera, which is also called a binocular stereoscopic camera, refers to herein a device to image an object from a plurality of different perspectives. Then, three-dimensional coordinate values corresponding to each pixel are calculated based on one set of two-dimensional images, for each of predetermined frames. It should be noted that the three-dimensional coordinate values calculated then are represented as a plurality of three-dimensional coordinates different for each perspective of the stereo camera. Thus, in the three-dimensional shape measurement system described in Non-Patent Literature 1, movement of the perspective of the stereo camera is estimated by tracking a feature point group contained in a plurality of two-dimensional images captured as dynamic images across a plurality of frames. Then, the three-dimensional model represented by a plurality of coordinate systems is integrated into a single coordinate system on the basis of the result of estimating the movement of the perspective to thereby generate a three-dimensional model of the object.
Non-Patent Literature 2 describes an example of a technique of generating a three-dimensional model of an object on the basis of a plurality of depth images (also called range images, or the like) acquired by moving an infrared depth sensor (hereinafter, referred to as an imaging unit). Such a depth image herein refers to an image representing pixel-basis distance information to the measured object. In the three-dimensional shape measurement system described in Non-Patent Literature 2, the infrared depth sensor is configured with an infrared projection unit, an infrared imaging unit, and a signal processing unit. The infrared projection unit projects a random speckle pattern to an object, and the reflected light is imaged by the infrared imaging unit. Then, based on deviation and change in the shape of the random speckle pattern imaged by the infrared imaging unit, the signal processing unit calculates the distance information to the object to thereby generate depth images. The configuration of the infrared depth sensor and the like are described, for example, in Patent Literatures 1 to 3.
A three-dimensional model of an object in the present invention refers a model represented by digitizing in a computer the shape of the object in a three-dimensional space. For example, the three-dimensional model refers to a point group model that reconstructs a surface profile of the object with a set of a plurality of points (i.e., a point group) in the three-dimensional space on the basis of a multi-perspective two-dimensional image or a two-dimensional image in which each pixel represents distance information. Three-dimensional shape measurement in the present invention refers to generating a three-dimensional model of an object by acquiring a plurality of two-dimensional images, and also refers to acquiring a plurality of two-dimensional images for generation of the three-dimensional model of an object.    Patent Literature 1: JP 2011-527790A    Patent Literature 2: JP 2009-511897A    Patent Literature 3: JP 2009-530604A    Non-Patent Literature 1: “Review of VR Model Automatic Generation Technique by Moving Stereo Camera Shot” by Hiroki UNTEN, Tomohito MASUDA, Toru MIHASHI, Makoto ANDO; Journal of the Virtual Reality Society of Japan, Vol. 12, No. 2, 2007    Non-Patent Literature 2: “KinectFusion: Real-time 3D Reconstruction and Interaction Using a Moving Depth Camera,” by Shahram Izadi, David Kim, Otmar Hilliges, David Molyneaux, Richard Newcombe, Pushmeet Kohli, Jamie Shotton, Steve Hodges, Dustin Freeman, Andrew Davison, and Andrew Fitzgibbon; October 2011, Publisher: ACM Symposium on User Interface Software and Technology, [Searched on Apr. 15, 2013], Internet <URL: http://research.microsoft.com/apps/pubs/default.aspx?id=155416>